Violent Shake/Shudder when Cabin Fan is On (Unrelated to Idle Speed)
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Violent Shake/Shudder when AC is On (AC - ONLY!) (Unrelated to Idle Speed)
Starting today, my car shakes/shudders/vibrates violently when I turn on the cabin's air. This occurs when I'm at idle or driving 40 mph so its not an idle speed issue. It does not occur when I hit the AC/OFF button on the dash. I don't know exactly what the stepper motor is or how its linked to anything else but I guess that or the blower probably aren't a problem since it doesn't do it when the cabin blows non-AC air. Lastly, it'll continue for several seconds when I shut the car down (and slowly stops as the fan or pulley or whatever it is related to in the engine bay slows down and stops spinning or whatever).
So my thoughts are that it is likely the AC compressor (this assumes the AC Off button disengages or otherwise lets the compressor/condensor pulley or whatever spin freely on the serpentine belt). I think its a mechanical issue, not electrical, since it'll continue for a few seconds even when the car is shut off.
Any thoughts?
So my thoughts are that it is likely the AC compressor (this assumes the AC Off button disengages or otherwise lets the compressor/condensor pulley or whatever spin freely on the serpentine belt). I think its a mechanical issue, not electrical, since it'll continue for a few seconds even when the car is shut off.
Any thoughts?
Last edited by govertime; Apr 28, 2009 at 10:30 AM.
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From: Huntington Beach, Ca.
'17 Jaguar XF
The only part that will continue spinning after the motor stops is the radiator fan. Mine has a balance weight on one of the blades.....it's just a U shaped piece of metal clipped to one of the blades. Check for loose fan/blade/fan motor/ mount etc. Watch it when it spins to see but be careful because if it is vibrating as much as you say it could come apart.
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The only part that will continue spinning after the motor stops is the radiator fan. Mine has a balance weight on one of the blades.....it's just a U shaped piece of metal clipped to one of the blades. Check for loose fan/blade/fan motor/ mount etc. Watch it when it spins to see but be careful because if it is vibrating as much as you say it could come apart.
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'17 Jaguar XF
The radiator fan only turns on (it's electric) when needed....to control motor over temp for example. AC is one of the conditions that turns on the fan if a sensor shows low pressure or temp at any one of several points. It's easy enough to just open your hood and look at the fan or feel the housing...is it vibrating?
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checked. its not the radiator fan.
I'm thinking the culprits is/are:
Does the blower run only when the a/c is regardless if ac is on/off?
Is there a separate AC only blower/fan?
The stepper motor is related only to vent direction, right?
I'm thinking the culprits is/are:
- compressor
- condensor
- stepper motor
- blower
Does the blower run only when the a/c is regardless if ac is on/off?
Is there a separate AC only blower/fan?
The stepper motor is related only to vent direction, right?
Last edited by govertime; Apr 27, 2009 at 03:25 PM.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
It's not a stepper motor & the compressor has no clutch & runs all the time. How can the condensor vibrate? That leaves the blower motor.
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Thanks Glyn
So all years have no clutch (mine is 2003)? This means its always being engaged by the belt right? I have a hard time wrapping my head around that
Does the blower run only when the a/c is regardless if ac is on/off? Because I can have the cabin air at full blast with the ac off but as soon as i turn it on. it gets crazy.
Is there a separate AC only blower/fan?
So all years have no clutch (mine is 2003)? This means its always being engaged by the belt right? I have a hard time wrapping my head around that
Does the blower run only when the a/c is regardless if ac is on/off? Because I can have the cabin air at full blast with the ac off but as soon as i turn it on. it gets crazy.
Is there a separate AC only blower/fan?
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
It has a single blower motor that only turns off when you crank the car. It is otherwise controlled by the fan switch. It does not turn on & off with a/c engagement.
All years have no clutch. The compressor runs all the time driven by the Poly V belt - It has an actuator that gets it pumping. This is common in modern vehicles - even Land Rover use it.
All years have no clutch. The compressor runs all the time driven by the Poly V belt - It has an actuator that gets it pumping. This is common in modern vehicles - even Land Rover use it.
Last edited by Glyn M Ruck; Apr 28, 2009 at 05:47 AM.
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From: Huntington Beach, Ca.
'17 Jaguar XF
When you are outside the car looking into the engine bay with the motor running and the hood open how do you determine the car's vibrating? Sound? Feel? And then when someone shuts it off how does the symptom dissipate?
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It has a single blower motor that only turns off when you crank the car. It is otherwise controlled by the fan switch. It does not turn on & off with a/c engagement.
The whole car shakes violently...like its going to disentegrate if I allow it to continue for a significant length. it seems to be originating from something on the belt. Its hard to pinpoint, because frankly the whole engine bay shakes so bad, yet alone any specific component on the belt.
I also just noticed a hissing vacuum leak-type sound emanating somewhere on the front top driver side of the engine (near the Throttle Valve/electronic gas actuator) but I haven't been able to determine if it is a loose hose or what. Just thought I'd point that out as it may/likely be related. This occurs regardless if the AC is on or off.
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'17 Jaguar XF
You may have bad motor mounts coupled with the notorious leaking vacuum hose. First stop the air leak and see what happens.
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motor mounts were replaced following a collision. if it were the motor mounts wouldn't occur regardless if the fan is blowing on/off and ac is on/off anyway?
i'll look for the "notorious vacuum leak". i noticed one of the hoses following the collision repair was loose a few months back but that was easily detected. this one is tougher to locate. anyway, i'm more interested in if this could be related to the violent shaking. my guess is its not.
i'll look for the "notorious vacuum leak". i noticed one of the hoses following the collision repair was loose a few months back but that was easily detected. this one is tougher to locate. anyway, i'm more interested in if this could be related to the violent shaking. my guess is its not.
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From: Huntington Beach, Ca.
'17 Jaguar XF
...i'll look for the "notorious vacuum leak". i noticed one of the hoses following the collision repair was loose a few months back but that was easily detected. this one is tougher to locate. anyway, i'm more interested in if this could be related to the violent shaking. my guess is its not.
How about the harmonic balancer? Maybe it got damaged in the accident and it's starting to come apart? And just a little more pressure on the belt from the AC causes it to fail? The thing that is weird about your symptoms is the continued shaking after the motor is shut down. Is it dieseling? That is...does it continue to run after turn off? Or does the motor stop turning and the shaking continue?
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i took another look at it last night. turns out its probably the fan after all. while it was spinning free, balanced, and otherwise fine under light load it turns out it kicks into high speed when the ac is active. that's when it appeared to be getting crazy. so i took a closer look and a sizeable piece is missing in the round band part that encircles the blades. i'm surprised that bit of plastic causes it to shake so terribly. it was in all likelihood overlooked following the collision. hopefully state farm will accommodate this repair. if not, i'll be STFF for a DIY on the fan.
the vacuum sound was a torn/deteriorated piece of hose. i think it was the one I'd mentioned in the previous post.
Ruck and mleskovar, i greatly appreciate your continued input. at the very least, its been documented on the forums some other things to check for should anyone have similar symptoms.
the vacuum sound was a torn/deteriorated piece of hose. i think it was the one I'd mentioned in the previous post.
Ruck and mleskovar, i greatly appreciate your continued input. at the very least, its been documented on the forums some other things to check for should anyone have similar symptoms.
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From: los angeles
2005 C230 k
my 05 had a similar issue where when i turned the A/C on the engine would shake and make a noise. took it the the dealer and they replaced the Belt tensioner-for single belt drive, R & R/ REPL . tension roll 271-200-02-70.
